Dyeing polyamide bonded fleece by dwelling with method complex azo dyestuffs

ABSTRACT

PROCESS FOR THE DYEING OF TEXTILE OF POLYAMIDE FIBERS BY PADDING THE SAID FIBROUS MATERIAL WITH CERTAIN ANIONIC DYESTUFFS, PREFERABLY SELECTED 1:2-METAL-COMPLEX DYESTUFFS, SUBSEQUENTLY WINDING UP THE PADDED MATERIAL ON A BATCH AND THEN ALLOWING IT TO DWELL FOR FIXING THE DYESTUFFS.

United States Patent US. Cl. 8-26 1 Claim ABSTRACT OF THE DISCLOSURE Process for the dyeing of textile fabrics of polyamide fibers by padding the said fibrous material with certain anionic dyestuffs, preferably selected 1:2-metal-complex dyestuffs, subsequently Winding up the padded material on a batch and then allowing it to dwell for fixing the dyestuffs.

The present invention relates to the dyeing of textile fabrics of polyamide fibers according to the dwelling process. I

Among the textile flat structures the non-woven articles have gained an ever-increasing importance. It is true that up to the present time predominantly cellulose fibers have been used as the basis for such fabrics, or at least those mixtures thereof in which only a comparatively small proportion consists of synthetic fibers. At present, this situation has changed in the sense that an increasing number of non-woven goods, especially fleeces, are sold in the market which consist entirely of synthetic fibers, predominantly of polyamide fibers. These goods may be dyed-the same as woven and knitted fabrics of polyamide material-according to the exhaust process either at the boil or under high temperature conditions.

Normally the said exhaust dyeing process is operated at temperatures within the range of from 90 to 135 C., preferably 95 to 130 C., the dyeing period depending on the polyamide source,'and on the aflinity as well as the diifusibility of the dyestulfs applied. The dyeing period generally ranges from 45 to 180 minutes. The dyeings so produced are after-treated in the conventional manner.

By means of fixing with hot air according to the Thermosol process there have, up to the present time, been dyed only woven and knitted fabrics of polyamide fibers with dispense and acid dyestuffs; under steaming conditions there have up to now only been applied disperse as well as acid dyestuffs and, under great difficulties, also 1 :2-metal-complex dyestuffs.

Now I have found that dyeings which exhibit fast shades can be produced on textile fabrics of polyamide fibers by padding the said fibrous material with certain anionic dyestuffs, preferably selected 1:2-metal-complex dyestuffs, subsequently winding the material up and then allowing it to dwell for fixing the dyestulf.

The dwelling process of the material padded with the dyestuffs is carried out according to the process of the invention at temperatures within the range of from 20 to 85 0., preferably at room temperature, for a period within the range of from 16 to 72 hours, peferably 16 to 24 hours. When the dwelling time is increased by a fur- 3,788,807 Patented Jan. 29, 1974 ther 24 hours, the shade does not undergo any alteration. At this low fixing temperature, good color yields are obtained as well as normal fastness properties.

For the operability of the claimed process it is immaterial in which form the textile fabrics of polyamide fibers are available: whether they are available in the form of set or loose fiber fleeces, or in the form of woven or knitted fabrics, in all cases a uniform dyeing is achieved after the dyestufl has been fixed according to the dwelling process. This must be mentioned especially in the case of polyamide fiber fleeces which fibers have been set by means of binder systems. It has up to now been possible with great difficulty only and by applying accurate operational methods to overcome the problem of producing a dyeing having an identical shade as well as depth of shade on the polyamide fleece and the binder since the two portions have different capacities for absorbing the dyestulf as well as different dyestulf affinities.

The use of an auxiliary agent for improving the solubility of the dyestuffs applied, for example a mixture of a polyglycol, especially of a polyethylene glycol having a molecular weight ranging from to 1000, and a polyalkylene glycol monoalkyl ether of low molecular weight, depends in the process of the invention on the concentration of the coloring substance, and should be practiced at least in the case of amounts of from 10 grams of dyestuff/liter of padding liquor upward, preferably in a ratio of 1:1 (calculated on the weight of the dyestuif).

In addition to the extraordinarily simple and cheap working method, the advantage of the process according to the invention resides in the insensitivity ,of the color yield with respect to alterations in the dwelling time. The said process can, therefore, be readily adapted to the sequence of operations of a textile finishing process. Largescale and expensive machinery can be dispensed with.

The dyeing procedure according to the present invention is carried out as follows: The dyestuffs are made into a paste together with a mixture of a polyglycoland a polyglycol ether, then boiling water is poured over the paste to obtain an acceptable solution of the dyestuffs. Then auxiliary agents which act as thickeners for the padding liquor, for example on the basis of ethers derived from carob-bean flour, are added to this solution, and the padding liquor is made up with water to a total volume of 1 liter. The pH of the bath is adjusted to a value of approximately 6 to 7 by the addition of an organic or inorganic acid or by means of a buffer mixture. The fibrous material is padded using a goods-to-liquor ratio of from 120.1 to 1:3, normally 1:1, at a temperature within the range of from 20 to 65 C., and the material is wound up. The batched material is then covered with cotton cloths or plastic sheets to avoid local drying on the surface or along the lateral edges of the package. In order to fix the dyestuffs the moist material is stored in a room protected from draft of air, preferably at room temperature. The dwelling process may, of course, also be carried out at an elevated temperature in a padroll installation. However, in this case the expenditure on machinery and energy is higher. It is advantageous to rotate the package of the material during the fixing or dwelling period.

As dyestuffs according to the process of the invention, 1:2-chromiumor lz2-cobalt-complex compounds of azo dyestuffs, especially of monoazo dyestuffs, are advantageously used, that is to say complex compounds in which two molecules of an azo dyestuff or 1 molecule each of two azo dyestuffs which differ from one another are bound in complex form to a chromium or cobalt atom. The complex compound may contain, for example, a disazo dyestuff and a monoazo dyestuff or, preferably, two identical or different monoazo dyestuff molecules. As groups forming metal complex compounds these azo dyestuffs preferably contain o,o'-dihydroxy azo groupings. Dyestuffs of said type are described in Colour Index, 2nd Ed. 1956, vol. 1.

As regards the operability of the process of the present invention, one skilled in the art would not expect that full, intense and acceptable dyeings of an even shade can be obtained on polyamide fleeces by storage at room temperature after a previous padding procedure with selected 1:2-metal-complex dyestuffs.

The following examples illustrate the invention:

EXAMPLE 1 2.5 grams of the 1:2-chromium-complex compound of the dyestuff of formula C I. Acid Orange were made into a paste together with 2.5 grams of a mixture of 1 part of a polyethylene glycol having a molecular weight of approximately 400 and 1 part of ethyl diglycol, and hot water was poured over the mixture, in which proceeding an acceptable dyestuff solution must be formed. To this solution were added 100 to 150 grams of a thickener on the basis of ethers derived from carob-bean flour (in dilution with water of approximately 1:5). The starting solution was then made up with a warm water to a total volume of padding liquor of 1 liter, the heat content of the water being sufficient to adjust, the temperature of the liquor to 50 to 65 C. The temperature of the bath should not decrease to a value below 50 C. since otherwise there is a danger of the dyestuff precipitating. By means of addition of approximately 0.5 ml./l. of a 60% acetic acid in the course of formulating said bath it was possible to adjust the pH of the liquor to a value of 6 to 7.

With the dyebath prepared in this manner a polyamide spun fleece was padded on a padding machine (squeezing eflfect 80%, calculated on the weight of the dry textile material) at a goods-to-liquor ratio of 1:1 and at a temperature of the liquor of 50 C., and the material was then wound up. The material was then covered with plastics sheets (as is the usual procedure in any pad-bath process to prevent local drying on the surface and along the lateral edges of the package) and it was stored in this state at room temperature. Drafts of air should be avoided as far as possible. After 16 to 24 hours dwelling time, the dyed material was rinsed for 60 seconds with water having a temperature of 60 C., then it was soaped for minutes at approximately 85 C. in a bath which contained per liter of water 1 to 2 grams of a non-ionic washing agent, it was again rinsed with water at 60 C. and then at 40 C., each time for 60 seconds, and finally the material was rinsed with cold water. A uniform intense, bright orange dyeing was obtained.

4 EXAMPLE 2 A combination consisting of 16 grams of the 1:2-chromium-complex compound of the dyestuffs of formulae HMS-Qbk-JI OH C1 OH I N=NI I j and 25 grams of the 1:2-chromium-complex compound of the dyestuff formula and H HN 0.1. Acid Orange 108 and 10 grams of the 1:2-cobalt-complex compound of the dyestuff of formula 0.1. Acid Black 140 was dissolved in a manner analogous to that of Example 1 and processed to give 1 liter of padding liquor. In the manner described in that example a polyamide fiber fleece was padded with this padding liquor, wound up and allowed to dwell for fixing the dyestutf. After rinsing and soaping a uniform navy blue dyeing was obtained.

EXAMPLE 3 grams of the 1:2-chromium-complex compound of the dyestuffs of formulae was made into a paste with denatured ethanol and dissolved in water. Using said padding liquor which was made up to 1 liter, in a manner analogous to Example 1, the pad-dyeing process was carried out in the manner as described in that example. In this manner a uniform dark anthracite was obtained on the polyamide fleece.

I claim:

1. A process for dyeing a bonded fleece of polyamide fibers to a uniform shade and depth of shade which comprises padding the fibers of said fleece with an aqueous liquor having a pH of 6 to 7 and which contains in solution a 1:2-chromiumor 1:2-cobaltcomplex compound of an anionic azo dyestutf or a mixture of such metal complex dyestuffs and an auxiliary agent consisting of a mixture of equal parts by weight of a polyethylene glycol having a molecular weight ranging from 150 to 1000 and a lower monoalkyl ether of a polyethylene glycol having 2 to 5 condensed ethylene oxide units, subsequently winding up the padded material and then allowing it in a moist state and in the wound-up condition to dwell at a temperature in the range of from 20 to 85 C. to fix the dyestuffs.

References Cited UNITED STATES PATENTS 3,223,470 12/1965 Boedeker et al. 8-54 X 3,208,990 9/ 1965 Benz et al. 8-43 X GEORGE F. LESMES, Primary Examiner 10 P. C. IVES, Assistant Examiner US. Cl. X.R. 

